Your teenage daughter needs her own space. Your home office is currently the dining table. And that box room you optimistically call a “study” is overflowing with stuff that has nowhere else to go.
Sound familiar? You’re not alone. Thousands of Australian families face the same space crunch every year. Adding a second storey seems like the perfect solution – more room without losing your backyard or moving away from the neighbourhood you love.
But here’s the question that keeps you up at night: Can you actually afford it?
Key Insights
- Second-storey additions in Australia typically cost between $380,000 and $650,000 (2025 figures).
- Building up costs 20-30% more per square metre than building out.
- The biggest cost savings come from simple designs, lightweight materials, and stacking wet areas.
- Many homeowners underestimate hidden costs like temporary accommodation and structural reinforcement.
- For some properties, building out or even knock-down rebuild may be more cost-effective.
Is Building Up Actually the Cheapest Option?
Let’s clear something up straight away: building a second storey is rarely the absolute cheapest way to add space to your home.
According to 2025 industry data, ground floor extensions cost between $2,500 and $4,000 per square metre, while second-storey additions run from $3,000 to $4,500 per square metre. That’s a significant difference when you’re adding 60 or 80 square metres.
So why do so many people choose to build up? Because sometimes math tells a different story.
If you’ve got a small block with limited backyard space, building out might mean sacrificing the outdoor area you actually use. Or maybe your neighbourhood has strict setback requirements that limit how far you can extend. In these cases, building up becomes the most practical option, even if it’s not technically the “cheapest” per square metre.
The real advantage? Building up often has fewer nasty surprises. Ground floor extensions can hit unexpected costs when excavators discover poor soil conditions or old tree roots. With a second storey, what you see in the quote is generally what you get.
The 7 Most Effective Ways to Cut Costs
After analysing dozens of second-storey projects, these strategies deliver the biggest savings:
1. Keep The Design Simple
Every architectural flourish costs money. That curved wall or fancy roofline might look stunning, but it’ll add thousands to your quote. A straightforward rectangular addition with a standard gable roof will always be your most affordable option. Complex designs require more engineering, more materials cut to specific angles, and more labour hours.
2. Use Lightweight Construction Materials
Here’s where you can save serious money. Timber or steel frame construction for your second storey is significantly cheaper than brick because it puts less load on your existing structure. Less weight means less (or sometimes no) foundation reinforcement is required.
3. Stack Your Wet Areas Vertically
This is the single smartest design decision you can make. Put your new bathroom directly above an existing bathroom, or position the upstairs kitchen above the downstairs one. Why? Because extending plumbing and electrical vertically through a single wall cavity is infinitely cheaper than running new pipes horizontally across your entire house. You’ll save on both materials and labour.
4. Reuse What You Already Have
If your roof tiles are in good condition, ask your builder about carefully removing them, building the second storey, and reinstalling the same tiles. This won’t work for every project, but when it does, you’ll save thousands on roofing materials. The same goes for any fixtures or fittings you can salvage and repurpose.
5. Choose Standard Finishes
The difference between $15 per square metre tiles and $50 per square metre tiles adds up shockingly fast. For a standard bathroom, that’s a $1,500 difference just in tiles. Multiply that across all your finishes and you’re looking at $20,000 to $30,000 in potential savings. Remember, you can always upgrade later when your budget recovers.
6. Do The Jobs That Don’t Need a Licence
Painting, landscaping after construction, and installing curtain rods are all tasks you can handle yourself if you’re reasonably handy. Just be realistic about your abilities. Amateur plumbing or electrical work will cost you far more in the long run when a licensed tradie has to fix it.
7. Consider Staging The Work
Build the structure now with standard finishes, then upgrade the kitchen or add built-in wardrobes in a year or two. This spreads the financial load, meaning you’re not maxing out your construction loan for nice-to-haves.
Hidden Costs That Blow Budgets
Every builder will give you a detailed quote. But here’s what often gets missed:
- Temporary accommodation: Depending on your builder’s approach, you might need to move out for weeks or even months. That’s rent or hotel costs on top of your mortgage. Budget at least $5,000 to $15,000 for this, or have a very accommodating relative.
- The staircase eats space: You’ll lose about half a bedroom’s worth of floor space downstairs to fit in a staircase. That’s not just construction cost – it’s the lost liveable area you’re paying for.
- Structural surprises. Even with a pre-construction assessment, sometimes engineers discover your existing frame needs more reinforcement than expected. Good builders include a contingency for exactly this reason.
- Council fees and professional services: Architect fees, engineer reports, council applications, and certifier costs can easily add $15,000 to $30,000 to your project. These are legal requirements and are not optional.
When a Second Storey ISN’T Worth It
Sometimes building up makes no financial sense. If your home sits on brick piers or a timber frame that can’t support additional load, the structural reinforcement could cost as much as the actual second storey. In these cases, a ground-floor extension or even a knock-down rebuild might be smarter.
Similarly, if you’re only after an extra bedroom and bathroom, you might find that a well-designed ground-floor extension gives you exactly what you need for significantly less money. Building up typically makes most sense when you need multiple rooms (ideally three bedrooms and a bathroom upstairs) to justify the fixed costs involved.
And if you’re planning to sell within five years? Think carefully. While second storeys can add substantial value, you might not recoup your investment quickly enough if the property market softens.
Ready to Explore Your Options?
The truth about building a second storey is that there’s no one-size-fits-all answer. What works for your neighbour’s block might be completely wrong for yours.
The cheapest approach isn’t always about finding the lowest quote, it’s about making smart decisions that balance cost with the value you’ll actually use. Sometimes that means building up. Other times, it means exploring house extensions that work with your existing structure rather than fighting against it.
At Go Build Co, we’ve helped dozens of Launceston families work through exactly these questions. We can assess your existing home, explain your realistic options, and give you honest advice about which approach will deliver the best value for your specific situation. Because the cheapest way to build a second storey is the one that doesn’t blow your budget halfway through.
